Food processors are used for various jobs in the kitchen. Examples include, inter alia, kneading, stirring and beating, to which end large mixing bowls are customarily used in which an appropriate tool, such as a kneading tool, a whisk-like agitating or beating tool, rotates. A further area of application for food processors of this type is slicing, shredding, grating and mixing with appropriate tools for performing such comminuting and mixing functions. For this area of application the food processor is equipped with a bowl unit of smaller capacity than a mixing bowl. Finally, a third area of application for such food processors is blending, but also chopping and comminuting, to which end an appropriately adapted container is mounted on the food processor.
Conventionally, the individual processing bowls are seated on a drive coupling or drive spindle which projects from the base unit and is centrally located with reference to a dished receptacle for accommodating the bowl. This drive spindle then engages in a mating hub member on the bottom of the bowl, which hub member extends into the interior of the bowl and drives the respective tool inside the bowl.
To be able to put food processors to more flexible use, such food processors are now equipped preferably with two bowl mounts, each of which is assigned a separate drive spindle. A matching processing bowl is then placed on its associated drive spindle. The two drive spindles can be driven at different rotational speeds by a single motor mounted in the base unit on account of different transmission ratios between the drive shaft of the motor and the particular drive spindle.
For safety reasons the processing bowls of such food processors are locked in their intended position in the base unit in order to create a secure driving connection between the processing bowl and the base unit and to ensure that the processing bowl remains firmly connected with the base unit during operation and particularly when a certain imbalance arises in the bowl due to uneven distribution of the food being processed.
On appliances of this type which possess several mounts for several processing bowls it should not be possible, for safety reasons, to fit several processing bowls simultaneously to the appliance in such a way that a driving connection is established between several processing bowls and the appliance.
Proceeding from the above described food processors, which have at least two separate mounts for one processing bowl each, it is an object of the present invention to equip such a food processor with a safety device which rules out the possibility of a simultaneous driving connection arising between several processing bowls on several drive spindles, such a safety device being desirably of simple and fail-proof design.